Molten metal level control for continuous casting

ABSTRACT

A molten metal level control includes a breakable tube for automatically feeding molten metal from a source to the mold, the tube having a first portion attached to the source and a second portion depending from the first portion. The control also includes float means mechanically coupled to said second tube portion for automatically controlling the rate at which the molten metal enters the mold from the breakable feed tube, and metering rod means positioned for coaction with said first portion of the breakable feed tube to provide uninterrupted regulation of the rate of flow of molten metal therethrough from the source and into the mold during emergencies when the second portion of the feed tube is broken from its first portion to eliminate automatic level control.

United States Patent 1 [111 3,738,419 Hartmann et al. [4 June 12, 1973 MOLTEN METAL LEVEL CONTROL FOR CONTINUOUS CASTING Primary ExaminerRobert D. Baldwin [75] Inventors: George J. Hartmann, Clark; Donald Attorney-Dams Home Falthfull & Hapgood J. Nesslage, Old Bridge, both of NJ.

[73] Assignee: Phelps Dodge Copper Products [57] ABSTRACT Corporation, New York, N .Y. A molten metal level control includes a breakable tube [22] Flled: 1971 for automatically feeding molten metal from a source [21] APPL 75 2 to the mold, the tube having a first portion attached to the source and a second portion depending from the first portion. The control also includes float means me- 52 US. Cl. 164/281 chanicauy coupled to said Second tube portion f [51] Int. Cl B2211 11/10 tomaticany controlling the rate at which the molten 58 Field of Search 164/281, 82,337 metal enters the mold from the breakable feed tube, and metering rod means positioned for coaction with References cued said first portion of the breakable feed tube to provide UNITED STATES PATENTS uninterrupted regulation of the rate of flow of molten 2,891,291 6/1959 Schnacke 164/281 x metal therethrough from the Source and into the mold 3,050,792 8/1962 Lipman et al...

164/281 during emergencies when the second portion of the 3,349,838 10/1967 Baier 164/281 feed tube is broken from its first portion to eliminate 3 4 5,811 9/1969 Castelet 164/281 automatic level control.

FOREIGN PATENTS OR APPLICATIONS 6 Cl i 2 D 1'' 745,546 5/1944 Germany 164/281 7 8 mung gum PAIENIEDM'ZW 357138.419

SHEEI 1 0F 2 l INVENTORS 650065 J l/ARIMAAW BY Dan/4w J lVESSZ AGE WJW AUWF/VEVF FlG.

MOLTEN METAL LEVEL CONTROL FOR CONTINUOUS CASTING The present invention relates to metal casting. More particularly, the present invention relates to an apparatus for molten metal level control in molds for the continuous casting of metal such as copper and copper alloys.

Various devices for maintaining the molten metal level in the continuous casting of metals are known in the art. Typical of such devices are those disclosed in US. Pat. No. 3,511,304 issued to Baier et al. on May 12, 1970, and 3,519,060 issued to Vischulis on July 7, 1970. These prior devices generally suffer from one or more of the following undesirable characteristics:

1. An inability to remove the device for emergency purposes;

2. The necessity of pre-heating prior to start-up to avoid freezing of the molten metal in the device;

3. The necessity of close tolerance fitting in the manufacturing stage; and/or 4. The use of costly, complicated electronic or radiographic equipment.

It is an object of the present invention to provide a molten metal level control which may be removed during emergencies without interrupting the casting procedure.

It is a further object of the present invention to provide a light-weight, reliable and low cost apparatus for automatically controlling the metal level in a continuous or semi-continuous casting mold.

It is a still further object of the present invention to eliminate the necessity for pre-heating prior to start-up.

Briefly, the apparatus for molten level control is arranged between the source and the mold to provide control of the level of molten metal in the mold. A breakable feed tube feeds molten metal from the source to the mold. Float means controls the rate at which the molten metal enters the mold from the breakable feed tube. Means is included for mechanically coupling the float means to the breakable feed tube. Metering rod means is positioned in the source for coaction with the breakable feed tube to provide uninterrupted regulation of the rate of flow of molten metal from the source through the remaining portion of the feed tube to the mold during emergencies when the molten metal level control is removed by breaking the feed tube below the source, eliminating metal flow control by the float means while the molten metal flow from the source to the mold is maintained and regulated by the interaction of the metering rod means with the portion of the feed tube which remains attached to the source. Splatter means plate deflects splattering metal away from the mechanical coupling means.

Other objects, aspects and advantages of the present invention will be more fully understood when the detailed description is considered in conjucntion with the drawings as follows:

FIG. 1 is a cross-sectional view of a casting machine employing the preferred embodiment of the present invention; and

FIG. 2 is a perspective view of the present invention broken away from the source.

Referring to FIG. 1 the molten metal level control is shown connected to a source 12 of molten metal and extending into a continuous casting mold 14 of a continuous casting machine 15. The source 12 may be a molten metal distributor located between the melting furnace and mold, or a melting furnace located directly over the mold. The molten metal level control 10 includes a breakable feed tube 16, a float means 18, mechanical coupling means generally indicated at 20, and a manual metering rod 22 positioned in the source 12 for vertical movement into engaging contact with the top opening 24 of the feed tube 16 during emergencies.

A specified level 26 of molten metal 28 in the mold 14 is constantly maintained by positioning the feed tube 16 at a predetermined distance from the top 29 of the mold 14. The solidified casting 30 is withdrawn from the mold in a vertical manner at a rate established for the casting machine 15. The molten metal 28 that is delivered to the mold l4 continuously moves in a generally vertical downward direction away from the feed tube 16 and float 18 toward the bottom of the mold 14 where the solidified casting 30 is removed.

The feed tube 16 is advantageously manufactured of a material which eliminates the necessity for preheating, e.g. fused silica. Further, the feed tube 16 has a minimum bore diameter which allows the molten metal to fill the mold at a faster rate than casting speeds specified for the casting machine 15. Advantageously, the feed tube may be readily broken below the source 12 during emergencies to provide uninterrupted casting. Control of the molten metal is then effected by moving the metering rod 22 into the top opening 24 in the remaining portion of the feed tube 16 to regulate the rate of flow of the molten metal from the source 12 to the mold 14.

The float means 18 is mechanically coupled to the feed tube 16 through mechanical coupling means 20. The float means 18 is generally cylindrical in shape with four equally spaced bottom holes 32 and eight equally spaced peripheral holes 34 which allow the molten metal to enter the mold 14 in a uniform manner with a minimum of turbulence. The float means 18 includes a cover or flange 36 connected to the sidewall 35 and parallel to the bottom 37 of the float means 18. The flange 36 may advantageously extend concentrically outward away from the feed tube 16 and/or concentrically inward toward the feed tube 16 to act as a partial cover or splatter shield to deflect splattering molten metal back into the mold 14. A conical shaped valve 38 is removably mounted at the center 40 of the bottom 37 of the float means 18. The valve 38 acts to control the rate at which molten metal passes from the bottom opening 42 of the feed tube 16 into the mold 14. The valve 38 also serves to help guide the float means 18 as it opens and closes the bottom opening 42 of the feed tube 16.

The float means 18 is advantageously manufactured of fused silica, graphite, or clay graphite, or any-other suitable light-weight material, and floats in the molten pool 28 at the top of the mold 14. Generally, the weight of the float 18 is chosen so that it floats in the molten pool 28 halfway submerged. The depth of submersion is determined by comparing the weight of the float means 18 with the buoyant force of the molten metal 28.

The mechanical coupling means 20 includes guide rods 44, sleeve 46, support 48, and bolts 50. The guide rods 44 are manufactured of a material, e.g. stainless steel, which can withstand the ambient operating temperature surrounding the area of the mold 14. The guide rods 44 are threaded at both ends and are attached to the support plate 48 and the float means 18,

generally at the flange 36, by means of nuts 52 which are preferably stainless steel. The guide rods 44 support the float means 18 during casting start-up and further function as vertical float guides during casting. The support plate 48 includes at least three equally spaced holes for bushings 54 which act as vertical guide for the guide rods 44, see FIG. 2. Stainless steel nuts 56 in combination with the bushings act as stops for the downward vertical movement of the guide rods 44. Three equally spaced threaded holes 58 are provided in the sleeve 56 for reception of bolts 50. The bolts 50 engage a channel 60 extending around the periphery of the feed tube 16. The channel 60 is placed at a suitable or convenient distance along the length of the feed tube 16, as shown in FIGS: 1 and 2, between the bottom 66 of the source 12 and the opening 42 of the feed tube 16. The bolts 50 are threaded into the holes 58 and engage channel 60 to support the float means 18.

An additional bottom plate or splatter plate 62 may be advantageously attached to the sleeve 46 to act as a metal splatter shield for deflecting molten metal away from the mechanical coupling means 20 to eliminate jamming caused by an accumulation of metal in the bushings 54 in the top plate 48. Three equally spaced oversized holes 64 are arranged in the bottom plate 62 to allow the guide rod to pass therethrough.

In operation the valve 38 partially enters the opening 42 at the bottom of the feed tube 16 as the molten metal pool 28 reaches the desired level 26. Should the molten pool 28 reach a level slightly higher than desired, the buoyant force on the float means 18 forces the valve 38 further into the opening 42 of the feed tube 16. This reduces the open area of the annulus formed between the valve 38 and the bottom 42 of the fed tube 16, thereby restricting molten metal flow. Conversely, if the level 26 of the molten pool 28 falls below that desired, the weight of the float means 18 causes it to move downward a corresponding distance, partially or fully removing the valve 38 from the opening 42 of the feed tube 16, so that the open area of the annulus formed between the valve 38 and bottom opening 42 is effectively increased allowing metal to flow into the mold 14 at a faster rate. The conical valve 38 may be constructed of the same or a different material than the float means 18. Further, the valve 38 may be changed periodically during use of the float means With the present invention, the desired level 26 of the molten pool 28 is attained during start-up of the casting machine and automatically maintained during the continuous casting operation at the desired level 26. Should an emergency occur during the automatic casting operation, the casting operation may continue uninterrupted by removing the float means 18 from the mold 14 by breaking the feed tube 16 below the bottom 66 of the source 12 and the channel 60, see FIG. 2. The countersunk top opening 24 in the remaining portion of the feed tube 16 attached to the source 12 is manually valved by the movable metering rod 22 which has a conical portion 68 for mating with countersunk top opening 24. The rate of flow of molten metal from the source 12 to the mold 14 is manually meterd by controlling the amount of open area of the annulus formed between the conical portion 68 of the metering rod 22 and the opening 24 in the feed tube 16. The desired level 26 of molten metal 28 in the mold 14 may therefore be continuously controlled even in emergencies.

It should be understood by those skilled in the art that various modifications may be made to the present invention without departing from the spirit or scope thereof as described in the specification and defined in the appended claims.

What is claimed is:

1. Apparatus for molten metal level control adapted for arrangement between a source of metal and a mold in a continuous casting machine to provide control of the level of the molten metal in the mold, comprising:

a breakable, vertically aligned feed tube for feeding molten metal from the source to the mold, said tube having a first portion attached to the source and a second portion depending from said first portion;

a cup-shaped float fitting freely on the end of the sec- 0nd portion of said breakable feed tube and adapted to float in the molten metal in the mold with at least its upper edge above the surface of the molten metal for automatically controlling the rate at which molten metal enters the mold through said breakable feed tube by vertical motion relative to said feed tube, the sides of said float being radially spaced from said feed tube so that there is no mechanical interaction between the sides of the float and the feed tube, said float having a first flange extending radially outward from its upper edge;

a second flange extending radially outward from the second portion of said breakable feed tube above said float;

a plurality of vertically aligned bushings through said second flange;

a plurality of parallel, vertically aligned guide rods attached to said first flange and extending through said bushings for coupling the float to the second portion of said feed tube and guiding the vertical movement of said float relative to said feed tube; and

metering rod means positioned for coaction with said first portion of said breakable feed tube to regulate the rate of flow of molten metal from the source to the mold through said first tube portion, whereby the float means can be removed by breaking said second portion of the tube from its said first portion, and thereafter continuous regulation of the level of the molten metal in the mold can be effected by adjustment of said metering rod means.

2. Apparatus as claimed in claim 1, including:

a splatter plate extending radially outward from the second portion of said breakable feed tube between said float and said second flange for deflecting splattering metal away from said bushings, said splatter plate having a plurality of apertures through which said guide rods pass without restraint. v

3. Apparatus as-claimed in claim 1, wherein:

said float and includes side and bottom flow holes for delivering molten metal to the mold with a minimum of turbulence.

4. Apparatus as claimed in claim 1, wherein:

said float includes a conical shaped valve arranged for partial and complete closing of said feed tube in the mold as said float undergoes vertical movement.

5. Apparatus as claimed in claim 4, wherein:

said conical shaped valve is removably mounted on said float for periodic replacement.

6. Apparatus as claimed in claim 1, wherein:

said breakable feed tube is made from fused silica. k 

1. Apparatus for molten metal level control adapted for arrangement beTween a source of metal and a mold in a continuous casting machine to provide control of the level of the molten metal in the mold, comprising: a breakable, vertically aligned feed tube for feeding molten metal from the source to the mold, said tube having a first portion attached to the source and a second portion depending from said first portion; a cup-shaped float fitting freely on the end of the second portion of said breakable feed tube and adapted to float in the molten metal in the mold with at least its upper edge above the surface of the molten metal for automatically controlling the rate at which molten metal enters the mold through said breakable feed tube by vertical motion relative to said feed tube, the sides of said float being radially spaced from said feed tube so that there is no mechanical interaction between the sides of the float and the feed tube, said float having a first flange extending radially outward from its upper edge; a second flange extending radially outward from the second portion of said breakable feed tube above said float; a plurality of vertically aligned bushings through said second flange; a plurality of parallel, vertically aligned guide rods attached to said first flange and extending through said bushings for coupling the float to the second portion of said feed tube and guiding the vertical movement of said float relative to said feed tube; and metering rod means positioned for coaction with said first portion of said breakable feed tube to regulate the rate of flow of molten metal from the source to the mold through said first tube portion, whereby the float means can be removed by breaking said second portion of the tube from its said first portion, and thereafter continuous regulation of the level of the molten metal in the mold can be effected by adjustment of said metering rod means.
 2. Apparatus as claimed in claim 1, including: a splatter plate extending radially outward from the second portion of said breakable feed tube between said float and said second flange for deflecting splattering metal away from said bushings, said splatter plate having a plurality of apertures through which said guide rods pass without restraint.
 3. Apparatus as claimed in claim 1, wherein: said float and includes side and bottom flow holes for delivering molten metal to the mold with a minimum of turbulence.
 4. Apparatus as claimed in claim 1, wherein: said float includes a conical shaped valve arranged for partial and complete closing of said feed tube in the mold as said float undergoes vertical movement.
 5. Apparatus as claimed in claim 4, wherein: said conical shaped valve is removably mounted on said float for periodic replacement.
 6. Apparatus as claimed in claim 1, wherein: said breakable feed tube is made from fused silica. 